Millimeter-Wave Band Electro-Optical Imaging System Using Polarization CMOS Image Sensor and Amplified Optical Local Oscillator Source

• Published in: Sensors (Basel, Switzerland) Vol. 24; no. 13; p. 4138
• Main Authors: Okada, Ryoma, Mizuno, Maya, Nagaoka, Tomoaki, Takehara, Hironari, Haruta, Makito, Tashiro, Hiroyuki, Ohta, Jun, Sasagawa, Kiyotaka
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 26.06.2024
• Subjects: CMOS image sensor; Crystals; Electric fields; electro-optic imaging system; Electromagnetism; Light; millimeter-wave imaging; on-pixel polarizer; Optics; Photonics; polarization image sensor; Sensors; Simulation; Wireless communications; on-pixel polarizer; millimeter-wave imaging; CMOS image sensor; polarization image sensor; electro-optic imaging system
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s24134138

In this study, we developed and demonstrated a millimeter-wave electric field imaging system using an electro-optic crystal and a highly sensitive polarization measurement technique using a polarization image sensor, which was fabricated using a 0.35-µm standard CMOS process. The polarization image sensor was equipped with differential amplifiers that amplified the difference between the 0° and 90° pixels. With the amplifier, the signal-to-noise ratio at low incident light levels was improved. Also, an optical modulator and a semiconductor optical amplifier were used to generate an optical local oscillator (LO) signal with a high modulation accuracy and sufficient optical intensity. By combining the amplified LO signal and a highly sensitive polarization imaging system, we successfully performed millimeter-wave electric field imaging with a spatial resolution of 30×60 µm at a rate of 1 FPS, corresponding to 2400 pixels/s.